Precision bore and method of producing same



Dec. 11, 1928. 1,695,017

PREQISION BORE mpumnon or momma 'sm 1 H. KUCKUGK Filed Nqv. 26.1927

I A'bforn eys Patented Dec. 11, 1928.

UNITED STATES.

PATENT OFFICE.

I HEHIBICH KUCKUCK, OF BREMEN, GERMANY.

PRECISION BORE AN]? METHOD OF PRODUCING SAME.

Application filed November 26, 1927, Serial No. 235,999, and in Germanylays, 1926.

The invention relates to precision or tol erance bores and a method ofmaking such bores which are to be a perforation or a-recess in an objectof metaL' Said bores are particularly adapted to form the seat ofbearings and to receive the rings of small ball or roller bearings usedin joints of me- Cl'l1{aI1lC3.l apparatus, such as prostheses or the lie.

The object of the invention is to devise bores for bearings or the like,which bores are of high accuracy in diameter, circular form andsmoothness and are suitable to receive delicate parts of a structure.

This object-is attained by the provision of a lining made of a materialcapable of being formed by pressing, and by giving the inner face of thesaid lining the required width and precision with the employment of 20 agauge mandrel, while at the same time joining the periphery of thelining to the part designed to receive the same, the operation beingperformed by upsettingor deforming the annular lining.

According to the invention, the housing or other part to be providedwiththe precise v bore is first formed with a preliminary bore, the diameterof which is somewhat greater than the external diameter of the outerring or rings of the roller or ball bearing or hearings to be insertedinto the precise bore, 'or of the shaft to be received by the precise ortolerance bore. The width of the bore made in the housing or casing mustbe sufiiciently greater than the external diameter of the part to beinserted into the precise bore as to enable an intermediate metal ringto be inserted into the said preliminary bore. The material of whichthis intermediate ring is made must have a lower elasticlimit than thematerial of which the housing is made. Preferably, the ring consists ofa soft metal or alloy which is malleable or deformable by pressure. 11order to produce the final exact bore, a gauge mandrel is now insertedinto the intermediate ring, the periphery of said gauge being ground orfinished to correspond exactly to the diameter and shape of the precisebore to be produced. This gauge mandrel takes the place of the part tobe finally received by the precise bore, for instance, a ball bearing ora roller bearing or a shaft. The intermediate metal ring is now firmlyfixed to the housing by a pressand deforming operation, by which themaance.

ing operation or by a combined upsettingterial of the intermediate ringis firmly pressed into the irregularities of the inner wall of thehousing and is thus caused to .like polished surface, the diameter ofthe borehaving the required exactsize within extremely narrow limits oferroror toler- This precise bore may therefore be used directly for thereception of a ball hearing or a roller hearing or a shaft. It will thusbe seen that the required exact bore can, in each case, be obtained bythe employment of suitably prepared gauge mandrels. It will beunderstood that in order to properly carry out the improved method, itis important that the specific pressure exerted by the body mountedwithin the bore of the intermediate ring should be less than the elasticlimit of the material employed for the intermediate ring, in orderto-avoid.

rapid wear of the bearing and oscillation of the shaft or part mountedtherein. W

It may also be pointed out that if an intermediate metal ring werepressed directly around the outer ring of a small ball hearing I placedinto the preliminary bore, there would be the danger of the outer ringof the ball bearing becoming subjected to unduly" high stresses duringthe pressing operation, and this might lead to a deformation of theouter ball bearing ring and consequently to a jamming of the ballswithin the ball bearing. Any risk of this lrind is entirely avoided bythe invention, as the ball bean ings may be quite safely inserted intothe precise bore thus made beforehand.

The invention is particularly advantageous in all cases in which thehearing or housing provided with the precise bore is to beelectro-plated, for instance, nickel plated, after the production of theprecise bore. In such cases the intermediate metal ring should be madeof a material which will not form a firm connection or combination withelectrode osit, so that the precisebore produced w' 1 not be deranged oraltered by the subsequent operation or electro-deposition. Such asuitable material may: be, for instance, duraluminium which during anickelplating operation will not combine with the nickel, but owing tothe presence of a galvanic reactive component (steel) ,'will receivemerely a coating of nickel which may be subsequently very easily removedwithout the employment of sharp tools. The emli ployment of such amaterial for the intermediate ring is essential for instance in the caseof joints used in themaking ofprostheses links.

In the accompanying drawing,. which forms a part of this specification,

.Fig. 1 diagrammatically illustrates the operative parts of an apparatusadapted to carry the method into practice, some of said,

parts being shown in vertical section, and Fig. 2 shows in .crosssection, a bear-ing device seated in a bore finished according .to theinvention.

Referring to the drawings, a indicates a housing or casing having a borewhich is bevelled at the edges. Into the bore of the housing a isinserted a ring-shaped strip of metal, which ring has lateral play inthe bore ofthe housing a, and also an internal gauge mandrel insertedinto the intermediate ring a. The gauge mandrel b is adapted internalsurface of the bore of the housing a,';and Is also at the same timepressed against thecylindric surface of the gauge mandrel b. Annulargrooves '57 or de ressions formed in the op 'te end faces 0 the ram (1and the table]: facilitate the outward spreading or flow of the materialof the ring 0 against the widened ends or beveled edges of the bore inthe housing a. By thereafter withdrawing the gauge mandrel from theintermediate ring 0 in the 'direction of the arrow Q, the requiredpreclse bore is completed,

In the drawing only the working elements of a ress are shown, while thepertinent parts pted to operate the said elements may e constructed aswell lmown in the art.

'Fig. 2 shows the, intermediate ring a after the completion of thepressing operation. It also shows a ball bearing inserted into saidring. It is advisable to remove the edges or burr e of the ring aprojecting on both sides of the housing a, for instance by means of amilling cutter, and it is also advisable to round off the precise boreat the edges f, as shown. p

The invention is articularl applicable to cases in which finisiiingbores y grinding or 7 otherwise are diflicult to make, or veryexsupported by a table It, the ring 0 is com-.

pensive, or inadvisable in view of. further treatment, for-instance,electro-plating. By dispensing with the necessity of ,a specialfinishing operation, the method hereinbefore described, apart fromsaving of costs, results in a product of high accuracy.

The invention is suitable for bearings in which the specific load thatis, the load per unit of area, is rather small, as especially in thecase of fairly small ball or roller bearings.

.In the foregoing specification and accompanying drawing I'havedisclosed, by way of examplefthe principle of my invention and themanner in which it may be. gen formed, but I do not wish to be limite tothe aforesaid details, but what I claim is- 1. A method of makingprecision or tolerance bores or seats of a determined size in a plate orhousing, characterized by making an oversized bore in the plate orhousing, placing an intermediate or lining ring within said bore,inserting a gauge mandrel through said ring and ,axially compressing therin 'to'the face of the bore while forming an sizing the ring by saidmandrel.

2. A method of making precision or tolerance bores or seats of adetermined size in a plate or housing member, characterized by axiallycompressing lining rings within oversized bores performed in the wallsof the. plate or housing member so as to bind the "same to the boresurfaces, while simultaneously formin the rings to proper size by agauge man rel.

3. A method of making precision or tol;

erance bores or seats of a determined size in a supporting member,characterized by preforming oversized bores therein, placing liningrings of soft metal within said oversized bores, forming the rings toprecise size by a gauge mandrel inserted therethrough and simultaneouslycompressing said rings axially around the mandrel so 'as to bind ls)ameto the inner walls or surfaces of the ores.

' 4.. A method of makingprecision or tolerance bores characterized byinserting a linin ring' within an oversized bore in a mem er, placingagauge mandrel within the ring and imparting reci rocal movement to themandrel while simu taneously applying axial compression to the ring,thereby causing-the latter to expand so as to fix itself firmly withinsaid bore and to attain a perfeet internal diameter or bearing surfacebe- '1 fore the mandrel is removedand the com- 1 pression released.

5.' A method of making precision or tol- 3 erance bores or seats of apredetermined size, characterized b inserting a lining ring within apreforme oversized bore or seat around a-gau e mandrel and axiallycompressing the "ring while simultaneousl" reciprocating the mandreltherewithin, w

by the ring under such compression is formed 'as a 'fixed element withinthe bore with its inner periphery or bearing surface calibratedaccording to the size of the mandrel. a

6. A method of making precision or tol-- erance bores or seats ofapredetermined size in a housing or supporting member, characterized byinserting a lining r1ng withm'a, preformed oversized bore or seat arounda gauge mandrel and axially compressing the ing to the size of themandrel, said ring being of a metal allo which does not electroplate soeasily ast e material of the housin or supporting member. a

g. 'A tolerance bore or seat in a housing or supporting member,comprising a lining ring compressed within a bore in the housing as afixed part of the latter with its inner bearin surface calibrated todesired size, saidrlng being of .a metal alloy such as duraluminiumwhich does not electroplate so easily as the material of the housmg orsupporting member in whic'h it is seated.

In testimony whereof -I have signed my name to this specification.

' HEINRICH KUCKUCK.

